Golf club head

ABSTRACT

A golf club head ( 1 ) whose volume is delimited by a crown ( 3 ), a sole-plate ( 11 ), a belt ( 4 ), and a hitting surface ( 2 ), junctions between the belt ( 4 ) and the hitting surface ( 2 ) delimiting a heel ( 9 ) and a toe ( 10 ). The belt ( 4 ) comprises at least one arc-shaped portion ( 8, 32, 33, 34, 35 ) which forms a visible layer of the belt ( 4 ), while extending along the belt ( 4 ) between the heel ( 9 ) and the tip ( 10 ), the arc-shaped portion ( 8, 32, 33, 34, 35 ) being a peripheral weight made of a high-density material.

BACKGROUND OF THE INVENTION

[0001] The invention relates to the field of golf and, moreparticularly, to golf club heads.

[0002] Each club must enable a player to impart to the ball a long,precise trajectory. The distance traveled by the ball increases as thedynamic loft of the club head becomes greater, and trajectory accuracyimproves as a function of head stability at the moment of impact on theball. For this reason, manufacturers seek to improve the mechanicalinertia of the heads.

[0003] Traditionally, golf club heads possessed homogeneous density;that is, they were made of solid wood or metal. These heads weredifficult to use because of their low mechanical inertia. When a strokewas poorly aligned, the ball traveled substantially off-line.

[0004] Next appeared hollow heads made of metal or composite materials.These heads provided greater mechanical inertia for a given weight,thereby improving the golfers' performance.

[0005] However, despite the various prior art solutions to achieveoptimal distribution of the weight of the head, many golfers still haddifficulty hitting their shots properly.

[0006] Current heads do not make it possible to obtain ball trajectoriesthat are simultaneously long and precise. In other words, present-dayheads do not incorporate weight distribution capable of providing at thesame time good dynamic loft and good stability upon impact.

SUMMARY OF THE INVENTION

[0007] The invention attempts to solve these problems by proposing agolf club head whose volume is delimited by the upper face, or crown,and a lower face, or sole plate, separated by a belt and a front, orhitting, surface, junction points of the belt and the hitting surfacedelimiting a heel and a toe.

[0008] According to the invention, the belt comprises at least onearc-shaped portion constituting a visible layer of the belt whileextending along the belt between the heel and the toe, the arc-shapedportion being a peripheral mass made of a high-density material.

[0009] This structure makes it possible to increase maximally themechanical inertia of the head as regards dynamic loft and stabilityupon impact. It follows, advantageously, that ball trajectories are bothlong and accurate.

[0010] According to a first embodiment, the head according to theinvention comprises a single arc-shaped portion which is continuousalong the belt from the heel to the toe. This structure facilitatesmanufacture and allows use of new, economical processes.

[0011] According to a first variant of the first embodiment, the headaccording to the invention comprises at least three parts, i.e., afirst, upper part incorporating the crown, the hitting surface, and anupper portion of the belt; a lower part including the sole-plate and alower portion of the belt; and an intermediate part constituted by thearc-shaped portion. This structure allows the use of materials ofdifferent kinds.

[0012] According to this first variant, the upper part, the lower part,and the intermediate part of the head are screwed together into oneassembly.

[0013] This assembly method facilitates the attachment and detachment ofthe head. It advantageously allows adjustment and maintenance of thehead.

[0014] According to a second variant of the first embodiment, the headcomprises two parts, i.e., the arc-shaped portion and a blockincorporating at least the crown, the belt, the sole-plate, and thehitting surface.

[0015] In this instance, it is easy to manufacture an impermeable blockthat can advantageously prevent the risks of dirt accumulation andheaviness of the head.

[0016] According to this second variant, the arc-shaped portion of thehead is made of a metallic copper alloy, and the block is made of atitanium-based metal alloy. This arrangement makes it possible tooptimize weight distribution and the inertial properties of the head,without impairing the impact-resistance thereof.

[0017] According to the second variant, the arc-shaped portion and theblock are welded together. This structure produces a more pleasant soundon impact and, consequently, allows the golfer to remain focused.

[0018] According to the first and second variants of the firstembodiment of the invention, the total weight of the head is between 185and 205 grams, the weight of the arc-shaped portion is between 40 and 60grams, and the volume of the head is between 250 and 270 cm³.

[0019] These parameters impart to the head the size which is mostreassuring to golfers, since it is neither too small nor too large andthus instills confidence in them.

[0020] According to a second embodiment, the head according to theinvention comprises two arc-shaped portions. In this case, whenconsidered together, the arc-shaped portions extend over at least 60% ofthe length of the belt, between the heel and the toe. This arrangementmakes it possible to adjust weight distribution specifically for anindividual golfer.

[0021] According to this second embodiment, the head comprises at leastthree parts, i.e., the two arc-shaped portions and a block incorporatingat least the crown, the belt, the sole-plate, and the hitting surface.This structure allows selection of at least two different materials formanufacture of the head. Furthermore, the two arc-shaped portions maypossess different densities. Accordingly, weight distribution specificto an individual golfer is further refined.

[0022] According to the second embodiment, the arc-shaped portions ofthe head are made of a metallic copper alloy and the block is made of atitanium-based metal alloy. In this case, the arc-shaped portions andthe block are welded together, the total weight of the head is between185 and 205 grams, the weight of each arc-shaped portion is between 16and 34 grams, and the volume of the head is between 250 and 270 cm³.

[0023] The structure disclosed by the second embodiment allows weight tobe balanced in a manner suited to the game of an amateur player.

[0024] The invention also relates to a process for producing a headpossessing the characteristics previously mentioned.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features and advantages of the invention will be betterunderstood from the following description provided with reference to theattached drawings illustrating, by means of examples, how the inventioncan be produced, and in which:

[0026]FIG. 1 is a perspective view of a head according to a firstvariant of a first embodiment of the invention;

[0027]FIG. 2 is a perspective view from another angle of the head inFIG. 1;

[0028]FIG. 3 shows a method for assembly of the head in FIGS. 1 and 2;

[0029]FIG. 4 is a second variant of the first embodiment;

[0030]FIG. 5 is a view similar to FIG. 4; and

[0031]FIG. 6 is a perspective view of a head according to a secondembodiment of the invention.

DETAILED DESCRIPTION

[0032] According to a first variant of a first embodiment, a head 1according to the invention is illustrated in perspective in FIG. 1, froman angle making it possible to distinguish a front, or hitting, surface2, and upper face, or crown, 3, a belt 4, and a hosel 5. The belt 4 inturn comprises an upper portion 6 and a lower portion 7 separated by astrip 8 whose function will be explained below. Two ends of the hittingsurface 2 form a heel 9 and a toe 10 at the spot where they connect withthe belt 4.

[0033] A view of the head 1 from another angle as illustrated in FIG. 2shows that a lower face, or sole-plate 11, is attached to the belt 4.The entire group of faces, including the hitting surface 2, the crown 3,the belt 4, and the sole-plate 11, form the jacket of a head 1, in thiscase the head of a metal-wood.

[0034] The head 1 is made of three main elements, as illustrated in anexploded view in FIG. 3:

[0035] a first, or upper, part 12 formed by the combination of the crown3, the hitting surface 2, the hosel 5, and the upper portion 6 of thebelt 4;

[0036] a second, or lower part 13 formed by the combination of thesole-plate 11 and the lower portion 7 of the center strip 4;

[0037] an intermediate part formed by the peripheral strip 8.

[0038] The upper part 12 is preferably produced using casting techniquesand a metal which may have a low density. For example, it is possible touse a titanium- or aluminum-based alloy. A steel could prove suitable,however, if the thickness of the faces is sufficiently thin, the goalbeing to produce a part 12 which is light in relation to the weight ofthe head 1.

[0039] The upper part 12 comprises means for connecting and positioningthe peripheral strip 8, which take the form, for example, of aperipheral edge 14 of the upper portion 6 and eyes 15, 16, 17, 18 in theupper part 12, which are spaced along the peripheral edge 14.

[0040] The peripheral edge 14 may be produced directly by casting, or itmay be machined. It functions as a surface supporting the peripheralstrip 8, which serves as a weight extending along the peripheral edge14, substantially from the heel 9 to the toe 10.

[0041] The peripheral strip, or weight, 8 preferably has a shapematching that of the peripheral edge 14 and of the eyes 15, 16, 17, 18.To this end, it comprises an arch 19 and projections 20, 21, 22, 23.

[0042] The weight 8 acts to add weight to the head 1 at the spot whereit is located, i.e., substantially on the sides and to the rear of thehead 1, but not on the front portion.

[0043] It is preferably made of a high-density material, e.g., an alloycontaining copper, tin, or other metal. A steel weight 8 may be suitableif it has sufficient thickness.

[0044] The lower part 13 is preferably supported both on the weight 8and on an inner side 24 of the hitting surface 2, so as to complete thejacket of the head 1. It is preferably made of a metal, in order to beboth light and wear-resistant. In fact, it is the weight 8 which mustgovern the dynamic performance of the head 1, while the sole-plate 11must resist friction on the ground.

[0045] Assembly means, for example screws 25, 26, 27, 28, are providedto hold together the upper part 12, the weight 8, and the lower part 13.

[0046] The screws 25, 26, 27, 28 extend simultaneously through the holesin the lower portion 7 of the belt 4 and through the holes in theprojections 20, 21, 22, 23 belonging to the weight 8, before beinghoused in the eyes 15, 16, 17, 18 in the upper portion 12. Thus, whenthe screws 25, 26, 27, 28 are tightened, the head 1 is assembled andready for use.

[0047] The structure of the head 1 makes it possible to position theweight 8 with great precision, in order to impart to the head 1 goodmechanical properties. In fact, the lateral portions of the weight 8adjoining the heel 9 and the toe 10 create a stabilizing effect duringrotation of the head 1 in relation to a vertical axis at the moment ofimpact on a ball. As a result, ball trajectories are more accurate.

[0048] The rear portion of the weight 8 allows the head 1 to pivotaround a substantially horizontal axis, by virtue of an inertialphenomenon called dynamic loft. This phenomenon occurs as a result ofclub shaft flection during the swing and helps accentuate the originalangle of inclination of the hitting surface 2. As a result, the ballsclimb higher into the air and travel farther.

[0049] Surprisingly, the continuous extension of the weight 8 along thebelt 4 makes it possible to combine the effect of stabilization duringrotation and the dynamic loft phenomenon in order to achieve optimaleffectiveness.

[0050] The head 1 is thus advantageously accurate and capable ofproducing long strokes.

[0051] Moreover, this structure facilitates manufacture enormously ascompared with traditional methods. In fact, it is not necessary to usecomplex cored molds comprising multiple parts, nor is it necessary tocarry out welding, sanding, or heat treatment operations. Productioncosts and time are thus advantageously reduced.

[0052] The head 1 produced is a hollow volume that can be filled with alight material capable of damping vibrations generated by impacts withthe ball. As one example, a plastic foam is highly effective.

[0053] The head 1 may be produced in accordance with other variants,such as that illustrated in FIG. 4.

[0054] For reasons of convenience, identical references are used todesignate the same components.

[0055] The head 1 according to this variant comprises a block formed byassembling the hitting surface 2, the crown 3, the sole-plate 11, thebelt 4, and the hosel 5. A recess 36 in the belt 4 and extending alongthe belt 4 substantially from the heel 9 to the toe 10 is provided tohouse an arc-shaped portion 32 made of a high-density material, theother parts of the head 1 being made of a material possessing lowerdensity. For example, the portion 32 is made of a copper-based metalalloy, while the rest of the head 1 is made of a titanium-based metalalloy. The arc-shaped portion 32 is assembled with the block of the head1 and is positioned in the recess 36, preferably in such a way that thevolume of the recess 36 is entirely filled by the arc-shaped portion 32.As a result, the volume of the head 1 remains unchanged despite thepresence of the arc-shaped portion 32. Any means of attaching the blockand the arc-shaped portion 32 can be used. For example, the portion 32can be welded to the block, with or without adding material in the form,for example, of a brazed seam, an electric spot weld, etc.

[0056] The two elements can also be-glued, screwed together, riveted,etc.

[0057] Another variant of the head 1 according to this embodiment isillustrated in FIG. 5. It differs from the variant in FIG. 4 only byvirtue of the fact that the shape of the arc-shaped portion and thehousing recess do not have uniform width. The arc-shaped portion 33incorporates three extensions 29, 30, 31 located respectively on the toe10 side, to the rear, and on the heel 9 side. These extensions 29, 30,31 of the arc-shaped portion 33 further improve the dynamic performanceof the head 1 while increasing its total weight, but without exceedingthe values which would make the golf swing difficult to perform.

[0058] Moreover, by virtue of their shape, these extensions 29, 30, 31combine with the sole-plate 11 to facilitate the movement of the head 1in the grass or in gravel. In fact, the shape of the sole-plate 11corresponds to the areas of heaviest friction and wear. Now, the hardermaterial used to manufacture the sole-plate 11 is relatively expensive.Consequently, savings are achieved by combining the extensions 29, 30,31 of the arc-shaped portion 33 with the shape of the sole-plate 11.

[0059]FIG. 6 illustrates a second embodiment of a head 1 according tothe invention. This head 1 comprises two arc-shaped portions 34, 35intended to be made integral with a block incorporating, in particular,the hitting surface 2, the sole-plate 11, the crown 3, the peripheralstrip 4, and the hosel 5. In this instance, the arc-shaped portions 34,35 partially fill cavities 37, 38 in the head 1 and are attached to thehead 1, as was previously described.

[0060] The cavities 37, 38 are open, but do not prevent the block fromretaining a volume substantially identical to that of the variants ofthe previous embodiment.

[0061] On the other hand, the shape of the arc-shaped portions 34, 35 ofthe cavities 37, 38 and of the sole-plate 11 are combined so as toensure simultaneously good dynamic equilibrium of the head 1 and theenhanced capacity to describe a line tangent to the ground during theswing.

[0062] In all of the variants and according to all of the embodiments ofthe invention, the head is distinguished from all other existing clubheads on the market by the fact that, for a given volume, inertialproperties are enhanced, since they are greater in magnitude.

[0063] Knowing that the golf market requires wood-type heads having avolume of approximately 260 cm³, the invention can be compared toexisting heads using the table below, in which:

[0064] each volume is given in cm³,

[0065] 13 is the mechanical inertia of the head in relation to avertical axis passing through the center of gravity when the head 1 isin the ball-address position, in g/mm²,

[0066] weights are expressed in grams. VOLUME 13 WEIGHT steel headcurrently sold 220 280 185-205 titanium head currently sold 260 290 to310 185-205 head according to the 260 310 to 340 185-205 invention

[0067] Preferably, the arc-shaped portion 8, 32, 33 weighs approximately50 grams and is between 40 and 60 grams. The arc-shaped portions 34, 35preferably weigh between 16 and 34 grams.

[0068] Furthermore, this type of construction can be used for all of theheads in a set of clubs.

1. Golf club head (1) whose volume is delimited by an upper face, orcrown (3) and a lower face or sole-plate (11) separated by a belt (4)and a front, or hitting, surface (2), junctions of the belt (4) and ofthe hitting surface (2) delimiting a heel (9) and a toe (10), whereinthe belt (4) comprises at least one arc-shaped portion (8, 32, 33, 34,35) which forms a visible layer of the belt (4), while extending alongthe belt (4) between the heel (9) and the toe (10), the arc-shapedportion (8, 32, 33, 34, 35) being a peripheral weight made of ahigh-density material.
 2. Head (1) according to claim 1 comprising anarc-shaped portion (8, 32, 33) which is continuous along the belt (4)from the heel (9) to the toe (10).
 3. Head (1) according to claim 1 ,wherein the head comprises three parts, i.e., an upper part (12)incorporating the crown (3), the hitting surface (2), and an upperportion (6) of the belt (4); a lower part (13) incorporating thesole-plate (11) and a lower portion (7) of the belt (4); and anintermediate part constituted by the arc-shaped portion (8).
 4. Head (1)according to claim 3 , wherein the upper part (12), the lower part (13),and the intermediate part (8) are screwed together.
 5. Head (1)according to claim 1 , comprising two parts, i.e., the arc-shapedportion (32, 33) and a block incorporating at least the crown (3), thebelt (4), the sole plate (11), and the hitting surface (2).
 6. Head (1)according to claim 5 , wherein the arc-shaped portion (32, 33) is madeof a copper metal alloy, and the block is made of a titanium-based metalalloy.
 7. Head (1) according to claim 5 , wherein the arc-shaped portion(32, 33) and the block are welded together.
 8. Head (1) according toclaim 2 , wherein the total weight of the head (1) is between 185 and205 grams, the weight of the arc-shaped portion (8, 32, 33) is between40 and 60 grams, and the volume of the head (1) is between 250 and 270cm³.
 9. Head (1) according to claim 1 , comprising two arc-shapedportions (34, 35), which, taken together, extend over at least 60% ofthe length of the belt (4) between the heel (9) and the toe (10). 10.Head (1) according to claim 9 , wherein said head comprises at leastthree parts, i.e., the arc-shaped portion (34), the arc-shaped portion(35), and a block comprising at least the crown (3), the belt (4), thesole-plate (11), and the hitting surface.
 11. Head (1) according toclaim 10 , wherein the arc-shaped portions (34, 35) are made of acopper-based metal alloy and the block is made of a titanium-based metalalloy.
 12. Head (1) according to claims 10, wherein the arc-shapedportions (34, 35) and the block are welded together.
 13. Head (1)according to claim 9 , wherein the total weight of the head (1) isbetween 185 and 205 grams, the weight of each arc-shaped portion (34,35) is between 16 and 34 grams, and the volume of the head (1) isbetween 250 and 270 cm³.
 14. Process for manufacture of a golf club head(1), the head (1) having a volume delimited by an upper face, or crown(3), and a lower face, or sole-plate (11) separated by a belt (4), and afront, or hitting, surface (2), junctions between the center strip (4)and of the hitting surface (2) delimiting heel (9) and a toe (10),wherein the head (1) is made by assembling two distinct elements, thefirst element being an arc-shaped portion (32, 33), which is a visiblelayer of the belt (4) extending along the belt (4) between the heel (9)and the toe (10), the second element being a block incorporating atleast the crown (3), the belt (4), the sole-plate (11), and the hittingsurface (2).
 15. Process according to claim 14 , wherein the arc-shapedportion (32, 33) is made using a high-density material such as a coppermetal alloy, and the block is made of a titanium-based metal alloy. 16.Process according to claim 14 , wherein the arc-shaped portion (32, 33)and the block are welded together.